1. Field of the Invention
The present invention relates to a hybrid vehicle equipped with an internal combustion engine and a motor respectively functioning to output driving power, and a control method of such a hybrid vehicle.
2. Description of the Prior Art
One known design of the hybrid vehicle has an auto cruise function enabling automatic constant-speed driving without requiring the driver's accelerator operation (see, for example, Japanese Patent Laid-Open No. 2005-020820). Another known design of the hybrid vehicle enables selection of a drive mode between a normal drive mode and a sports drive mode (see, for example, Japanese Patent Laid-Open No. 2005-124282). In selection of the normal drive mode, the hybrid vehicle sets a torque demand required for driving based on the driver's accelerator operation amount and subsequently sets a target drive point (defined by a combination of a target rotation speed and a target torque) of an internal combustion engine or a motor based on the torque demand. In selection of the sports drive mode, on the other hand, the hybrid vehicle specifies a minimum engine rotation speed as a lower limit of the engine rotation speed corresponding to the vehicle speed and sets the target drive point of the internal combustion engine to keep the engine rotation speed higher than the minimum engine rotation speed.
Combined application of the selection of the drive mode with the auto cruise function for attaining, for example, constant-speed driving desirably satisfies the driver's diverse needs. The hybrid vehicle of this application may, however, require undesirably complicated control or cause the driver to feel awkward in a certain combination of the drive mode and the auto cruise function.